STUDIES ON THE DYNAMICALLY VULCANIZED POLYPROPYLENE (PP) BUTADIENE STYRENE BLOCK-COPOLYMER (SBS) BLENDS - MELT RHEOLOGICAL PROPERTIES

Unvulcanized and dynamically vulcanized blends of isotactic polypropyl ene (PP) and butadiene-styrene block copolymer (SBS), in the compositi on range of 10-40 wt % SBS content are prepared in an internal mixer a nd the vulcanization process is investigated through time-torque curve s. Study of melt rheological properties of these blends are reported, and results show the effects of blend composition and shear rate on me lt viscosity and melt elasticity. Blending of PP with SBS increases me lt viscosity and decreases extrudate distortion. Dynamically vulcanize d blends show higher melt viscosity and lower melt elasticity than cor responding unvulcanized blends with no melt fracture in the studied ra nge. (C) 1997 John Wiley & Sons, Inc.